Manufacture of threads, filaments, and the like from viscose



u s I v M O R F E K I L E H T D N A S T N E M A L I F S D A E R H T F Om U C A F U N A M Jan. 29, 1946.

D. s. DAWSON Filed Jan. 27, 1942 fig. 2. HERLAND DAWSON SUT 6y is 2292?meys Patented Jan. 29, 1946 MANUFACTURE OF THREADS,

THE LIKE FROM VISCOSE Daniel Sutherland Dawson, Tettenhall,Wolverhampton, England, nssignor to Courtaulds Limlted, London, England,a British company Application January 27, 1942, Serial No. 428,435 InGreat Britain February 6, 19:41

2 Claims. 18--8) The common method or producting threads, filaments andthe like from viscose consists in extruding the viscose through holesinto a bath containing sulphuric acid and sodium sulphate filaments arethereby injured and possibly broken.

It has therefore been customary to maintain a certain amount of humidityin the atmosphere with which the thread comes into contact, and sincethe higher the percentage of sodium sulphate in the spinning bath thegreater will be the tendency for it to crystallise out on the thread, ithas been desirable to employ a spinning room atmosphere "in which thehumidity is greater when greater concentrations of sodium sulphate areemployed in the spinning bath. Under some conditions of working, thehumidity required to avoid crystallisation of sodium sulphate on thethread is so high that the atmosphere becomes oppressive to the workmen.

It has already been proposed-in the Huttinger Patent 2,042,529 for thepurpose of removing salt deposits from the spinning box or the walls ofthe small chamber containing the spinning box, to project a spray of asalt-dissolving liquid, such as water, against the outer surface of thespinning box or against the inner wall of the small chamber within whichthe spinning box is situated. Obviously such treatment can have noefiect on the thread before it reaches the spinning box. I hav now foundthat considerable advantages are obtained when producing irom viscosethreads, filaments and the like,

which will hereinafter be referred to as threads, by extruding the saidviscose into a bath containing sulphuric acid'and sodium sulphate, withor without other ingredients, if the thread be enclosed during itspassage from the bath to the collecting device and one Or more sprays ofwater, either in the liquid or gaseous state, he intro duced inside theenclosure of the thread. One convenient method of enclosing the threadis by enclosing the spinning machine;

The humidity 01' the air introduced into the workshop is then preferablymaintained at a relatively low figure. By means, or the sprays, water isintroduced in the form or vapour or very finely divided droplets andthis greatly reduces the tendency of the sodium sulphate to crystallise,or even prevents it from crystallising, on the threads or on to theother parts of the machine, thus avoiding damage to the threads, to thespinning machine or to the workmens hands. It is also unnecessary tointroduce into the workshop air with such a high degree of humidity asis injurious o unpleasant to the workmen.

The process oi. this invention is of particular use when the viscose isbeing spun into a bath containing say 16 per cent or more of sodiumsulphate. The spray of water or aqueous vapour can be employed at theordinary or at a raised temperature, and the process can even be carriedout by blowing steam into the enclosure of the threads or machine. Theenclosing of the machine can be effected in any suitable manner; forinstance, the known method of effecting an enclosure by means of glasswindows is convenient.

The drawing accompanying this specification will assist in illustratingthe nature of this invention, but the invention is not restricted to themethod and apparatus shown in the drawing.

In the drawing-Figure 1 represents a crosssectlon through a spinningmachine, showing sufiicient parts to enable the invention to beunderstood, while Figure 2 is a sketch showing part of the machine. Inone or both of these drawings A represents the pump which delivers theviscose through the candle filter B to the nozzle C. The thread D, whichis formed as the viscose leaves the nozzle, passes through a guide E,shown only in Figure l, to the first godet F, thence to the second godetG and through the funnel H into the centrifugal box J. The front of themachine is closed during normal working by means of windows K, which arehinged at L. The spray of water or watervapour is introduced through aseries of spraying nozzles, of which one, marked M, is shown in eachfigure. Air is drawn from the machine through the chamber N surroundingthe spinning box, and also if desired through holes P in the back of themachine in the neighbourhood of the second godet G.

In the following claims, the term "Water is used in a sufilcientlygeneral sense to apply whether it be in a liquid or gaseous state.

What I claim is: 1. In the production of artificial threads byprojecting viscose through a periorated nozzle into an aqueous spinningbath containing sulphuric acid and at least one metallic salt. themethod which comprises passing the thread from the spinning bath whiledamp and in an unwashed condition through a relatively long path fromthe spinning bath to the collecting device and within an enclosed airspace, and simultaneously spraying finely divided water into saidenclosed air space to create a moist atmosphere extending along the pathof the thread as it passes through said enclosed air space, whereby thetendency of the metallic salt of the spinning bath to crystallize on theunwashed thread is reduced 2. In a machine for the production ofartificial threads by projecting viscose through a periorated nozzleinto an aqueous spinning bath containing sulphuric acid and at least onemetallic salt, the combination of a closed container including a threadforming section, a spinning bath within said thread forming section, aspinning nozzle in said bath, a thread collecting device,.meanstor-guiding the formed thread while still damp and in an unwashedcondition throu h the thread forming section and to the threadcollecting device, and means for spraying finely divided water into thethread forming section to create a moist atmosphere therein to reducethe tendency for the metallic salt of the spinning bath to crystallizeon the thread as said thread is guided through section.

DANIEL SUTHERLAND DAWSON.

the thread forming

